Many camera based products, such as videophones, webcams and mobile devices, require wide angle lenses. In order to avoid having their faces look too small, users tend to move their faces close to the camera. As a result, perspective distance effects become large and their faces appear distorted in the image, with large noses and pinched cheeks. Users find this unflattering. This distance-based perspective effect is an undesirable feature of videophone and video email products.
There are other perspective effects such as wide-angle (fish-eye) distortion and oblique distortion (which causes keystoning). Compensation techniques have been proposed for mitigating these effects, but these techniques are not applicable to the type of distortion described above.